Do it for the polar bears!

WASHINGTON — For marketers, climate guilt isn't the easiest thing to sell. Part of the audience doesn't have it and doesn't want it; they think climate change is fake, fuzzy or too far in the future to care about. And another segment of the audience already has too much of it. They believe in climate change so fervently that they're too paralyzed or resigned to respond to new messages. • So can you change all these minds with a single ad? • U.S. environmental groups have focused on the bright side, playing up the side benefits of tackling greenhouse gases. But in other countries, some activist groups and governments have used much darker messages.

This ad, produced by the British ministry for climate change, has been the subject of complaints from TV viewers who think it's too scary for children. It uses a variation on an old theme, emphasizing the problems that today's children will inherit in a warming world. In this spot, that problem looks like a giant sky-monster that makes bunnies weep and drowns puppies in the sea.

2. Stop polluting, or animals get it!

This spot, from the Portuguese environmental group Quercus, is among the most startling ads that focus on the threats to animals. It bypasses the slow drama of actual biology and shows animals committing suicide because of climate change. A trio of despondent mammals — an ape, a polar bear and a kangaroo — are living in hellish landscapes of deforestation, shrinking ice caps and drought. Then the ape loops a rope around its neck, the polar bear pitches itself off a cliff, and the kangaroo hops in front of a speeding freight train. The message: "If you give up, they give up."

3. Stop polluting, or you'll get it!

This ad, produced by the Belgian firm Germaine for the World Wildlife Fund, is among those trying to rebut the argument that climate change is an issue for some other generation. These kinds of ads tell readers that climate change will be a problem in their lifetime — by bringing droughts, stronger storms or rising seas. This one, however, makes an unusual threat that, at least so far, doesn't seem to be backed up by science: It says climate change will turn you into a merman.

4. Stop polluting, you big jerk!

These types of ads try to show high-polluting Westerners the way others (or at least some environmentalists) see them: as revolting knuckleheads. In this spot, produced by two Canadians for a contest run by the British branch of the charity OxFam, an energy-wasting man is confronted by a man from a drought-ridden African village, who calls him a nasty name and, Three-Stooges-style, hits him with a pie. In the last scene, we see the villager walking away, with a wagon full of pies for the rest of us.

American strategy

Most mainstream U.S. environmental groups, trying to build support for climate legislation, have backed off the scare tactics and focused instead on side benefits such as green jobs and reduced dependence on foreign oil.

Their ads often don't mention the words "warming" or "climate change" — and there's no sign of crying bunnies.

David A. Fahrenthold (fahrenthold@washpost.com) covers the environment for the Washington Post.